Coating with metals.



We Drawing.

A with metals by projecting powdered metal,

' citizen of the United York city, in. the county of New York,

State of New York, have invented certain s rAEn'r orsrcE.

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COATING WITH METALS.

To all whom it may concern:

Be it known that I FLOYD J. Mn'rzonn, a states, residing at New new and useful Improvementsin Coating with Metals; and I do hereby declare the following to be a full, clear, and exact. de-.

scription of'the invention, such as will enable others skilled inthe art to which it pertains to make and use the same. g

This invention relates to improvements in coating with metals, and more particularly I low ng constituents: nlckel, copper, chroto coating processesin which th e'metal projected in a finely divided state upon the surface to be coated.

It has heretofore been proposed to coat either in a molten or unmolten state, upon the object to be coated. It has also been proposed to coat with metals by melting a metal wire and spraying-the molten 'metal upon the object to be coated. To this end it has been, proposed to feed the metal, in

.wire or powder form, to or through the nozzle of an oxyacetylene torch. The metal becomes melted at the tip of the torch and is projected against the object to be coated by means of high pressure gas.

In so far as I am aware, acetylene is the combustible heretofore used in the process referred to. There are, however, a number of disadvantages resulting from its use.

When acetylene is used in the oxyacetylene torch, it is necessary to operate the torch at some distance from the object to be sprayed in order to prevent back firing of I jthe acetylene.

"the metal does not reach its ob ect1ve wlth sufficient force and the requislte temperature As a result a greatdeal of to make it adhere, but is largely dissipated into the surrounding air with resulting loss .7 to the coating operation.

Acetylene is itself of an unstable compo-- sition and readily decomposed, particularly as it issues from the tip of a blow pipe or torch, and when it comes into contact with the hot wire or hot metal. The metal tends to catalyze and promote this decomposition. In other words, the hot wire or metal tends to break up the acetylene into. carbon and hydrogen with the resulting gradual formation of a deposit of carbon on the tip of the torch which soon interferes with the proper operation of the torch. This catalytic de- S p'ecincation of Letters Patent Application filed Uoto'ber 80, 1918;; Serial No. 280,282.

- solvent or absorbent.

, Patented Apr. 8, 191a.

composition, although it ismore or less general is especially marked when certain particular metals or alloys are employed in the spraying process. For example, in the case of nichrome wire, which is composed essentially of an alloy of nickel,"chromium, iron and manganese, this catalytic decomposition takes place very readily, forming a deposit of carbon on the end of the torch inavery short time. This catalytic decomtends to be projected with the metal spray and to change the composition of the metallic layer produced therewith, much as in thecase where the oxyacetylene torch is employed in cutting and welding operations.

Acetylene, moreover, cannot be directly compressed in containers, but-requires to. be absorbed in a suitable solvent or absorbent therewlth. As a result, the acetylene is available only as it is 'ven oil from the her objections to the employment of acetylene in oxyacetylene torches and blow pipes are well known, and need no further elaboration.

According to the present invention, the ob ectlons incident to and resulting from the employment of acetylene in oxyacetylene blow pipes employed for the spraying of metal are largely overcome or minimized, and the coating operation is moreover carrled out in an improved and advantageous manner.

According to the present invention, there 1s supplled to the coating or spraying blowpipe or torch a combustible gas consisting essentially of ethylene. Ethylene can be produced in various ways, for example, by

' the dehydration of ethyl alcohol, or by its age and shipment of compressed oxygen without any such dangeror objections-as are involved in thestorage and shipment of acetylene.

position of the acetylene would be most not- 'able with such metals as nickel or cop er \Vhen the blowpipe or torch flame is produccd with the aid of ethylene and oxygen, it has a characteristic smoothness which distinguishes it from the oxyacetylene flame. The ethylene flame, moreover, is substantially free from tendency to back fire while its temperature is nevertheless comparable with and even higher than that of the oxyacetylene flame.

In the coating process of the present invention, the metal Wire may be fed through the nozzle of the oxyethylcne torch in any suitable manner and melted and projected upon the object to be coated, but the operation of melting and projecting the metal has the important advantage that the melting and projecting torch or blowpipe can be operated practically in. contact with the object to be sprayed or within about i of an inch or less of the object. As a result, a concentrated blast of sprayed metal is produced which is directly transported to the object to be coated, and readily finds its mark and adheres well, while very little of the atomized metal is dissipated into the surrounding air. The objections and limitations involved in the use of acetylene, and in the operation of the coating torch at a considerable distance away from the object are thus largely overcome.

By operating the oxyethylene torch in close proximity to the object to be sprayed, the density of the deposit and the continuity of the layer can be very materially increased and improved. That is, the operation of the torch at a distance from the 0b j ect tends to give a distinctly porous coating as well as a relatively less dense coating, while the operation of the torch in close proximity to the object according to the present invention results in increased den' sity of the coating and increased compactness of the layer formed.

For many purposes, it is highly desirable to make deposited coating as dense as possible. For example, in attempting to make lead linings for iron vessels by spraying, it has been impossible, in so far as am aware, to form a deposit sufficiently dense to withstand the action of acids (when acetylene is employed in the coating process). In other words, the lead deposited by prior processes would not be suitable for a container of diluted sulfuric acid because of its porous nature. According to the present invention, a dense deposit can be dlrectly produced, inasmuch as the torch can beoperated very close to the ob ectto be sprayed. As a result, the objection to the porous coatings produced with the oxyacetylene torch can be thus largely overcome. Th1s advantage ofincreased density is applicable not only to lead coatings, such as lead 11nings of iron vessels, but it is generally applicable to other coated ob ects inasmuch as it is usually important to make the coating o iflcovering of the object as compact as poss1 e.

The operation of the coating process with ethylene as the combustible gas has the furtheir advantage that catalytic decomposition and carbonization, such as result from the use of acetylene, do not take place to any objectionable extent, and the coating produced is correspondingly benefited by the *absence, or substantial absence, of carbon and modification therefrom.

Where the coating torch is held at some distance from the object to be sprayed or coated, there is an increased tendency toward oxidation of the coated metal, particularly in the case of certain easily oxidizable metals, such as copper or alloys containing copper. This objectionable oxidation can be largely reduced or overcome by carrying out the spraying or coating operation with the aid of ethylene, inasmuch as the torch can be held much closer to the object than has heretofore been possible when acetylene is employed.

The coating process of the present invention can be practised with different types of torches or blowpipes, including those commonly employed with acetylene for coating purposes. The metal wire may thus be fed through the nozzle of the oxyacetylene torch and the feed of the wire regulated in accordance with the rate of melting. The spraying and coating operation can be promoted by the supply of high pressure air or other high pressure gas in a manner similar to that employed in apparatus with which acetylene is used.

The process of the present invention, as above noted, is generally applicable to the coating with various metals, and even with materials which are essentially nonmetallic, inasmuch as the high temperatures resulting from the employment of ethylene make it possible to use even diflicultly fusible materials, and inasmuch as the smoothness and flexibility of the ethylene flame make it genobjections and disadvantages and enables the necessary high temperatures to be obtained and a dense coating to be produced without objectionable formation of carbon, and without the tendency to porosity incident to employing the torch at a considerable distance from the object to be coated. The process of the present invention, accordingly, is available for use with increased advantage for producing dense and compact coatings of these diificultly1 fusible alloys. 7

Inasmuch, however, as t e employment of ethylene gives to the torch increased smoothness and flexibility, it is possible to employ the coating torch at a considerable distance from the object to be coated, and still obtain many of the advantages incident to the employment of the ethylene.

Instead of supplying the coating metal to the 'coating torch in wire form, it can also be siipplied in powdered form, for example, by feeding it to or through the oxyethylene flanie of the torch in regulated amount, and

many of the advantages incident to the practice fof the invention will still be "obtained" I claim:

1. lhe method of coating metal and other objects with metal by supplying to a coating torch a combustible gas consisting essentially of ethylene together with oxygen, supplying the coating metal to the flame thus produced, and promoting the metal upon the object to be coated.

' 2. The method of coating metal and other objects with metal by supplying to the coatin'g torch a combustible gas consisting amentially of ethylene together with oxygen, melting the coating metal with the flame thus produced, and projecting the "molten metal upon the object-to he coated from a point in close proximity'to the object whereby a dense compact coating is obtained.

3. The method of coating metal and other objects with diflicultly fusible alloys containing nickel and chromium which comprises supplying to a coating torch a com bustible gas consisting essentially of ethylene together with oxygen, melting the alloy with the oxyethylene flame thus produced, and projecting the molten alloy nponthe object to be coated to produce a dense compact coating;

In testimony whereof I aifix my signature.

- ,I. 'IZGER.

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